Tel: ; Keywords: seeds, electromagnetic treatment, laboratory germination, surfaces and lines of response

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1 STUDY OF LABORATORY GERMINATION OF SEEDS FROM MILYANA TOMATO VARIETY AFTER ELECTROMAGNETIC TREATMENT / ИЗСЛЕДВАНЕ НА ЛАБОРАТОРНАТА КЪЛНЯЕМОСТ НА СЕМЕНА ОТ ДОМАТИ, СОРТ МИЛЯНА, СЛЕД ПРЕДСЕИТБЕНИ ЕЛЕКТРОМАГНИТНИ ОБРАБОТКИ Assoc. Prof. PhD Eng. Sirakov K. ), Assoc. Prof. PhD Ganeva D. ), PhD Eng. Zahariev S. ), Prof. PhD Eng. Palov I. ), Prof. PhD Eng. Mihov M. ) ) Angel Kanchev University of Ruse, Bulgaria; ) Maritsa Vegetable Crops Research Institute, Plovdiv, Bulgaria Tel: ; csirakov@uni-ruse.bg Keywords: seeds, electromagnetic treatment, laboratory germination, surfaces and lines of response ABSTRACT After pre-sowing electromagnetic treatments by epanded eperimental plan from В type and after theoretical studies of the constructed response surfaces and lines of the response laboratory germination of the seeds from tomato variety Milyana it was theoretically confirmed that the positive results are obtained in the following values of the controlled factors: voltage of treatments U= kv, duration of treatment =5 s and length of stay to sowing Т= days. It is proven that an effective impact could be obtained in combined increase of the controlled factor voltage of treatment and shortening of the duration of treatment = s. РЕЗЮМЕ След предсеитбени електромагнитни обработки по разширен план на експеримента от типа В и теоретични изследвания на построените повърхнини и линии на отклика лабораторна кълняемост на семена от домати сорт Миляна, теоретично е потвърдено, че положителни резултати се получават при стойности на управляемите фактори: напрежение на обработка U= kv, продължителност на въздействие =5 s и продължителност на престоя от обработката до засяването Т= денонощия. Доказано е, че ефективно въздействие може да се получи и при съчетано увеличаване стойността на управляемия фактор напрежение на обработка и съкращаване продължителността на въздействие = s. INTRODUCTION The seeds are carriers of morphological, biological and economical characters and properties of the plants and their quality reflects in a great degree on the productivity and quality of the variety produce. (Danailov, 0). High quality of the seeds is a base for development of normal plants (Poryazov I. et al., 0). The growth power of the seeds influences the further development of the new grown plants and has particularly strong effect on their vegetative growth and, therefore on the productivity (TeKrony and Egli, 99). The seeds with greater germination energy and germination give quick and total germination, faster development, and smaller susceptibility to the unfavourable conditions. The competence and correct application of the pre sowing treatment of the seed could be an efficient mean for increasing the sowing qualities of the cereal, technical and vegetable crops seeds (Sirakov, 006; Radevska M. et al., 0). The results from study, the effect of pre-sowing electromagnetic treatments on the laboratory properties of seeds from tomato variety Milyana are shown in (Ganeva D. et al., 04). A stimulation effect of parameters of the electromagnetic treatment, namely voltage of treatments U= kv, duration of treatment =5 s and length of seed stay from treatment to sowing Т= days were established. It was achieved an increase of germination energy with 0.60%/c, laboratory germination with 04.60%/c, hypocotyls length with 5.7%, cotyledons length with.88%, root length with 4.4% as well as an increase of the plant fresh weight with 5.00% towards the control (untreated) seeds. In other parameters of the pre-sowing treatment (U=6 kv, =5 s and stay to seed set for germination Т=4 days) was established a depressive effect on the seed development the length of the roots, hypocotyls and cotyledons were by (6 0)% smaller compared to the control and the plant fresh weight has been increased with over %. According to the above considerations, the investigations were continued and the seed laboratory germination was established after conducting of pre-sowing electromagnetic treatment of the seeds by etended plan В (Mitkov, 0), and the response surface and lines of response were obtained. 5

2 The purpose of the study was the probable values of the controlled factors stimulating more effectively the laboratory germination of tomato seeds from Variety Milyana to be established by means of the etended plan of the eperiment of pre-sowing electromagnetic treatments. MATERIAL AND METHOD An object of study was the laboratory germination of tomato seeds from variety Milyana namely, determinate, large fruited variety suitable for mid-early field production. The seed germination is within (9 9.50)%. Controlled factors of the pre-sowing electromagnetic treatment in the AC corona discharge field are: voltage U (kv) between the electrodes (edge-plane) and the duration of treatment (s). After treatment the seeds were left for stay Т (days) till their set for germination. The pre-sowing treatment was conducted on the -st of March 04. The tomato seeds were set in Petri dishes with wet filter paper for germination in controlled conditions in thermostat at temperature 5 о С and relative humidity 95%. In each variant were set 00 seeds in 4 replications after 4, 8 and day stay in electromagnetic treatment (International Seed Testing Association, 004; Ganeva D. et al., 04, 05; Sirakov K. et al., 05). The laboratory germination of the seeds was established for each eperiment (4, 8 and days) at 4 th day of sowing. Data were given in percentage towards the controls (%/c). The results were mathematically processed (Mitkov, 0), and response surfaces and lines of response were obtained ( RESULTS The pre-sowing electromagnetic treatments were conducted by three factorial eperiments according to symmetrical constructional plan from В type (Mitkov, 0). The values of the controlled factors and their corresponding levels of variation are shown in Table. Table Factors Voltage, U Duration of impact, Length of stay, Т Controlled factors Level of controlled factors high medium low + kv 0 9 kv - 6 kv + 5 s 0 0 s - 5 s + days 0 8 days - 4 days The plan of the eperiment with the results established for the laboratory seed germination is given in Table. The reported average values of the laboratory germination (g) of the controlled seeds are the following: the germination in stay of the treated seeds for 4 days is g=9.5%, in stay of 8 days the germination is g=9.00%, and after stay of days g=9.50%. Towards them the obtained results for laboratory germination of the seeds Y for each variant of treatment and relevant stay are given in %/c. According to the results ( Y i ), given in Table for the established laboratory germination of the particular variants of treatment by plan В, and according (Mitkov, 0) the equation for regression was found. This equation epresses the relation between the laboratory germination and the combination of the individual factors (voltage U of treatment factor, duration of treatment factor, length Т of stay to set of the seeds for germination factor ) and their interactions:,,,, and : By the control (Mitkov, 0) it was established that the equation () is adequate according to the comparison of the calculated criteria of Fisher with its critical value. On the basis of the critical value of the Student s criteria it was established that the coefficients of regression in the equation are significant. 54

3 Variants Eperiment planning matri Controlled factors Laboratory germination, Y, %/c - U, kv -, s - Т, days Table Ŷ 0,6 0,96 0,0 99,764 0,89 0,90 0, 0,069 0,676 (),046 The response surfaces and lines of response are studied for evaluation of the influence and interaction between the factors on the laboratory germination. They are composed according (Mitkov, 0), and the programme product Statistica 8 ( The response surfaces and lines of response are obtained as a result of consecutive elimination of each one of the factors, and, and the other two vary between the levels given in Table. Since the number of the controlled factors is, the obtained and analyzed response surfaces and lines of response are by. It is known the presence of correlation between the quadratic members itself i of the equation (). This forces to calculate the remaining coefficients of the model (Mitkov, 0) again in elimination of some quadratic members. It should be mentioned that in this calculation, the values of the free member and non-eliminated members were only changed. Variant : The factor duration of stay Т is eliminated. In that case, in interaction of the factors and the equation of the response surface is of the following kind: Ŷ 00,66 0,89 0,90 0,069,57 0,4 () In use of the Statistica 8 ( it was built the response surface (Figure а) and lines of response (Figure b) laboratory seed germination in function of the voltage applied between the electrodes (U) and time of electromagnetic treatment (), in case of elimination the influence of the factor duration The values of from Figure. (Т) of stay from treatment to seeds sowing. Ŷ, for model (), in %/c, are given in numerical type on the ordinate of the drawings 55

4 a b Fig. Response surface (a) and lines of response (b) laboratory germination as a function of factors (U) and (), (Т) switched off factor The effect ( Ŷ in %/c) of the impact of the pre-sowing electromagnetic treatments of the seeds, obtained by the model (), is shown in Figure а and Figure b by different colours (according to the legend of Figure ) in the response surface and lines of response themselves. Moreover, where the dark green fields are, for eample in =( ) and =( ), the pre-sowing impact should be depressing. In case of accepting the values of the two factors in natural units it could be said that the depressing impact of the pre-sowing electromagnetic treatment on the laboratory germination should be epected in combination of the two factors in the limits U=(9.6 6.) kv and =( ) s. Then the laboratory germination of the seeds will be smaller (i.e. <00%/к) compared to the control/untreated seeds in electromagnetic field. Bright green, yellow and etc. to dark brown areas, for eample in =( ) and =(+. -.) demonstrate that the selected values of the two controlled factors of pre-sowing treatment influence stimulating in a different degree on the observed parameter laboratory germination which is epected to eceed to % that one of the controlled seeds. When the values of the two factors are taken in natural units it could be said that the stimulating impact of the pre-sowing electromagnetic treatment on the laboratory germination is epected in combination of two factors in the limits U=(0.5.6) kv and =(8 ) s. The laboratory germination in this case will be over 0%/c towards that of the controlled/untreated in electromagnetic field seeds. According to Figure а and Figure b it could be concluded that in the adopted upper levels of the controlled factors = (i.е. U= kv) and = (i.е. =5 s), a stimulating pre-sowing effect is obtained the value of the laboratory germination will be over 0%/c. In these values of the controlled factors in (Ganeva D. et al., 04) is described that the laboratory germination of the pre-sowing treated seeds was g = 04.60%/c towards the control. According to Figure b it could be established that in increase of the values of the two factors which are studied, for eample =+. (i.е. U=.6 kv) and =+. (i.е. =8 s) it should be epected an increase of the laboratory germination of the seeds of over 0%/c. In this respect eperiments should be conducted for pre-sowing electromagnetic treatments of the seeds by using of risen values of the two controlled factors. It should take into considerations that the ecessive increase of the values of the applied voltage could not be achieved by technical reasons because prob- 56

5 ably the corona discharge between the two electrodes could develop in spark discharge and then in arc electric discharge which would results in damage burning of the seeds. On the basis of the Figure а and Figure b, it could be established that in decrease of the values of the two factors it should epect a stimulation of the seed laboratory germination up to % towards the controls. This could be obtained in voltage =-. (i.е. U=5.4 kv) and duration of treatment =-. (i.e. = s). According to Figure а and Figure b, it could be established that an increase effect of stimulation of the laboratory germination (over % towards the control) could be also obtained in the following values of the two factors: =+. (i.е. U=.6 kv) and =-. (i.е. = s). Therefore, the treatment of the seeds in the above mentioned increased voltage of the corona electrical discharge should be short as an impulse (in this case for seconds). On the other hand, this would contribute for greater increase of the voltage value applied for pre sowing treatment and decrease of the probability for electrical break between the electrodes. Variant : The factor applied voltage between the electrodes U is eliminated. The equation of the response surface in the interaction of the factors Ŷ and is: 00,6 0,90 0, 0,6 0,,57 () Figure а and Figure b demonstrate the response surface and lines of response laboratory germination of the seeds in function of the duration of electromagnetic treatment () and length of stay (Т) from treatment to set of seeds for germination that are built by (). The impact of the pre sowing electromagnetic treatments of the seeds is shown in different coloured zones in Figure as well as in Figure. a b Fig. Response surface (a) and lines of response (b) laboratory germination as a function of factors () and (Т), (U) switched off factor The analysis of Figure a and Figure b demonstrates that in eliminated factor and in values of the controlled factors ( ) and Т ( ) as follows: within (+. -.) and the pre sowing electromagnetic treatment will be with inhibiting effect. within ( ), 57

6 When the values of the factors are in natural units the inhibiting effect of the pre sowing electromagnetic treatment on the laboratory germination is epected in combination of the two factors in the limits =(8 ) s and Т=(0 6) days. The laboratory germination of the seeds in this case will be smaller (i.е. <00%/c) than that of the control/untreated seeds. According to Figure а and Figure b could be concluded that an increase of the effect from pre sowing electromagnetic impact i.e. an increase of laboratory germination from 0%/c to over 0%/c could be obtained in combination of the values of the two controlled factors in the limits =(+. -.) and =( ), respectively. When the values are in natural units, the stimulation effect of the pre sowing electromagnetic treatment on the laboratory germination could be epected in combination of the two factors in the limits =(8 ) s and Т=( ) days. Then the laboratory seed germination will be greater (over 0%/c) than that of the control/untreated seeds. Variant : In this variant the factor duration of the electromagnetic impact was eliminated. In this case in the interaction of the factors Ŷ and the equation of the response surface is: 99,80 0,89 0, 0,676 0,99,069 (4) Figure а and Figure b show, respectively the response surface and lines of response laboratory germination of the seeds in function of voltage (U) of the electromagnetic treatment and length (Т) of stay from treatment to set the seeds for germination, built by the Model (4). The analysis of Figure а and Figure b demonstrates that in eliminated factor the two controlled factors U ( ) and Т ( ) as follows: within ( ) and.), the pre sowing electromagnetic impact will be inhibiting. and in values of within ( a b Fig. Response surface (a) and lines of response (b) laboratory germination as a function of factors (U) and (Т), () switched off factor When the values of the controlled factors are in natural units the inhibiting effect of the pre sowing electromagnetic treatment on the laboratory germination could be epected in combination of the factors duration of treatment =0 s with the remaining two factors in the limits U=( ) kv and Т=approimately ( ) days. In this case the laboratory germination of the seeds will be smaller (<00%/к) then that of the controls/untreated seeds. 58

7 The analysis of the Figure а and Figure b demonstrates that it is necessary the two controlled factors (U) and (Т) to be with equal values or with greater values over the levels accepted as upper ones, i.е. factor and for stimulation of the laboratory germination with over 0%/c. Therefore if the is accepted at the mean level, i.e. =0 (=0 s), the voltage of treatment should be accept- ed U kv and the length of stay Т days. The obtained theoretical results are confirmed by the presented in (Ganeva D. et al., 04, 05; Sirakov K. et al., 05). Data demonstrates that as a result of the performed laboratory investigations after pre sowing electromagnetic treatments of the seeds from tomato variety Milyana by variant Table (U= kv and =5 s) and length of the stay of the seeds to their set for germination Т= days and Т=65 days, the obtained results are the following: in Т= days stay, the laboratory germination is stimulated to 4.6% over that of the control seeds, the root length of the germinated seeds to 4.4%, of the hypo cotyledons to 5.7%, of the cotyledons.88% and the fresh plant weight to 5.00%; in 65 days stay, the laboratory germination is increased over 9%, the root length over 47%, the length of the hypo cotyledons over.87% and that of the cotyledons over 6%. According to that described above, it could be mentioned that by eperimental (Ganeva D. et al., 04, 05; Sirakov K. et al., 05), and theoretical way is shown that in order to be obtained a stimulating effect of the pre sowing electromagnetic treatment of the seeds from tomato variety Milyana it is necessary that the controlled factor values to be higher for voltage U kv, for duration of treatment 5 s and length of stay to set of the seeds for germination Т=( to 65) days, respectively. Similar stimulation effect could be epected when the pre sowing electromagnetic treatment is short/impulse with duration = s and voltage U kv, and Т=( to 65) days from treatment to sowing. CONCLUSIONS. On the basis of the performed laboratory investigations (Ganeva D. et al., 04, 05; Sirakov K. et al., 05), was established that the effective impact on the sowing properties of tomato seeds from variety Milyana could be obtained after pre sowing electromagnetic treatments in use of controlled factors with the following values: voltage of treatment U= kv, duration of treatment =5 s, length of stay from treatment to seed set for germination Т= days. It was established that the positive effect as a result of pre sowing treatment is kept after 65 days from the treatment in U= kv and =5 s.. It is proved that after pre sowing electromagnetic treatment by etend plan of the eperiment from B type and theoretical studies of the built response surfaces and lines of response laboratory germination: a) Positive results are obtained in the following values of the controlled factors: voltage of treatment U= kv, duration of treatment =5 s and length of stay from treatment to sowing Т= days; b) Efficient impact could be obtained in increase of the controlled factor values: voltage of treatment U over kv, duration of treatment over 5 s and length of stay T of the seeds from treatment to sowing over days; c) Efficient impact should epect in combined increase of the values for controlled factor voltage of treatment and shortening of the duration of treatment to s.. Theoretically established possibilities for efficient stimulation of the sowing properties and morphological characters of tomato seeds after pre sowing electromagnetic treatments should be eamined in laboratory and field studies. REFERENCES [] Danailov Zh., (0), Breeding and seed production of tomato (Solanum lycopersicum L.). History, methods, achievements, trends (Селекция и семепроизводство на домати (Solanum lycopersicum L.). История, методи, постижения, тенденции), Prof. M. Drinov Academic Publishing House, Sofia/Bulgaria; 59

8 [] Ganeva D., Sirakov K., Mihov M., Martev K., Zahariev S., Palov I., (04), Influence of pre-sowing electromagnetic treatments on propagating seed qualities of tomato variety Milyana (Влияние на предсеитбените електромагнитни обработки и срока на съхранение върху кълняемата енергия и лабораторната кълняемост на семена от български сортове домати), Proceedings of the International Symposium ISB-INMA TEH`04, pp , Bucharest/Romania; [] Ganeva D., Sirakov K., Mihov M., Zahariev S., Palov I., (05), Influence of pre-sowing electromagnetic treatments and duration of storage on germination energy and laboratory germination of seeds from Bulgarian tomato varieties (Влияние на предсеитбените електромагнитни обработки и срока на съхранение върху кълняемата енергия и лабораторната кълняемост на семена от български сортове домати), INMATEH Agricultural Engineering, vol.45, Issue, pp.4-50, Bucharest/Romania,; [4] International Seed Testing Association, (ISTA), (004), International rules for seed testing. Bassersdorf, Switzerland; [5] Mitkov A., (0), Theory of eperiment (Теория на експеримента), Dunavpress Publishing House, Rouse/Bulgaria; [6] Poryazov I., Petkova V., Tomlekova N., (0), Vegetable growing (Зеленчукопроизводство), Dimi- 99 Publishing Hause, Sofia/Bulgaria; [7] Radevska M., Stoilova A., Palov I., Sirakov K., (0), Impact of electromagnetic treatment and storage term on the pre-sowing properties of cotton seeds. І. Laboratory germination (Влияние на електромагнитната обработка и срока на съхранение върху посевните качества на семена от паму І. Лабораторна кълняемост). Plant Science, vol.49, Issue, pp. 9-7, Sofia/Bulgaria; [8] Sirakov K., (006), Results of study after pre-sowing electromagnetic treatment of maize seed of Bulgarian and American hybrids (Резултати от изследване след предсеитбени електромагнитни обработки на царевични семена от български и американски хибриди). Scientific works of A. Kanchev University of Ruse/Bulgaria, vol. 46, Issue., pp.87-9; [9] Sirakov K., Ganeva D., Zahariev S., Palov I., Mihov M., (05), Results of the investigation regarding the influence of pre-sowing electromagnetic treatment and storage period on sprouting of seeds of Bulgarian tomato varieties (Резултати от изследване влиянието на предсеитбените електромагнитни обработки и срока на съхранение върху прорастването на семена от български сортове домати), Ecology and Future, vol. 4, Issue -, pp. 65-7, Sofia/Bulgaria; [0] TeKrony D.M., Egli D.B., (99), Relationship of seed vigor to crop yield: A Review, Crop Science, Madison/WI, vol., Issue, pp. 86-8; [] *** 60